Synthesis and crystal structure of an analogue of the uranyl( VI ) ion, containing a linear OUN– group

The crystal structure of the air-stable compound PPh4+[UOCl4{NP(m-Tol)3}]–(m-Tol = C6H4Me-m) shows that it contains a linear (179°) OUN–group, with U–O and U–N distances of 176 and 190 pm respectively, coordinated by four chlorine atoms; the U–O distance is typical of uranyl compounds, and the U–N distance suggests a bond order >2.